Green synthesis of AgNPs-dithizone@chitosan for highly selective and reusable electrochemical sensors of Hg2+

Modification of screen-printed electrodes using silver nanoparticles-dithizone@chitosan was carried out to obtain highly selective and reusable sensors of Hg2+. This study aims to greenly synthesize AgNPs-Dtz@Cts and modify carbon screen-printed electrodes as selective and reusable sensors for Hg2+ detection. The AgNPs were synthesized using an ultrasound-assisted method with eco-freiendly reducing agent of Hydrocolyte umbellata leaves extract. The formation of AgNPs was validated by UV–Vis spectra showing the presence of the surface plasmon resonance band at 405 nm and FTIR spectrum showing the decrease of hydroxyl and carbonyl HU extract absorption peaks. TEM profile shows that AgNPs are spherical with an average diameter range of 5.36–16.71 nm. The modification of SPEs-AgNPs-Dtz@Cts was successfully fabricated. The modified sensor showed good stability as a reusable sensor and high selectivity for mercury detection. The SPEs-AgNPs(4)Dtz@Cts exhibited the most optimum electrochemically active surface area of 14.91 mm2 and optimum sensitivity of 1.78 × 10−6 A/(V/s). The sensor exhibited a satisfactory limit detection for the detection of Hg2+ in the concentration range of 1 to 5 ppb. The SPEs-AgNPs(4)Dtz@Cts showed ultratrace detection of Hg2+ with LOD and LOQ values of 0.06 and 0.19 ppb, respectively with the sensitivity was 7.72 ± 0.43 μA/ppb. Determination of Hg2+ using SPEs-AgNPs(4)Dtz@Cts sensor has good precision and accuracy with % RSD = 1.71 % and % recovery 98.13 ± 0.02 %. Therefore, the designed sensor has the potential for highly selective, reusable sensors, low-cost, and miniaturization Hg2+ detection in real samples.